Measles

Measles, also known as rubeola or morbilli, is an infection of the respiratory system caused by a virus, specifically a paramyxovirus of the genus Morbillivirus. Morbilliviruses, like other paramyxoviruses, are enveloped, single-stranded, negative-sense RNA viruses. Symptoms include fever, cough, runny nose, red eyes and a generalized, maculopapular, erythematous rash.

Measles (also sometimes known as English Measles) is spread through respiration (contact with fluids from an infected person's nose and mouth, either directly or through aerosol transmission), and is highly contagious—90% of people without immunity sharing living space with an infected person will catch it. An asymptomatic incubation period occurs nine to twelve days from initial exposure and infectivity lasts from two to four days prior, until two to five days following the onset of the rash (i.e. four to nine days infectivity in total).

An alternative name for measles in English-speaking countries is rubeola, which is sometimes confused with rubella (German measles); the diseases are unrelated.